US11637541B2 - Joined body and elastic wave element - Google Patents

Joined body and elastic wave element Download PDF

Info

Publication number
US11637541B2
US11637541B2 US16/796,036 US202016796036A US11637541B2 US 11637541 B2 US11637541 B2 US 11637541B2 US 202016796036 A US202016796036 A US 202016796036A US 11637541 B2 US11637541 B2 US 11637541B2
Authority
US
United States
Prior art keywords
supporting substrate
piezoelectric material
layer
material layer
ratio
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active, expires
Application number
US16/796,036
Other languages
English (en)
Other versions
US20200195217A1 (en
Inventor
Masashi Goto
Tomoyoshi Tai
Mai Minoura
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NGK Insulators Ltd
Original Assignee
NGK Insulators Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NGK Insulators Ltd filed Critical NGK Insulators Ltd
Assigned to NGK INSULATORS, LTD. reassignment NGK INSULATORS, LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: GOTO, MASASHI, MINOURA, MAI, TAI, TOMOYOSHI
Publication of US20200195217A1 publication Critical patent/US20200195217A1/en
Application granted granted Critical
Publication of US11637541B2 publication Critical patent/US11637541B2/en
Active legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02535—Details of surface acoustic wave devices
    • H03H9/02818—Means for compensation or elimination of undesirable effects
    • H03H9/02826—Means for compensation or elimination of undesirable effects of adherence
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02535—Details of surface acoustic wave devices
    • H03H9/02543—Characteristics of substrate, e.g. cutting angles
    • H03H9/02574—Characteristics of substrate, e.g. cutting angles of combined substrates, multilayered substrates, piezoelectrical layers on not-piezoelectrical substrate
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02535—Details of surface acoustic wave devices
    • H03H9/02543—Characteristics of substrate, e.g. cutting angles
    • H03H9/02559—Characteristics of substrate, e.g. cutting angles of lithium niobate or lithium-tantalate substrates
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
    • H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
    • H03H3/08—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of resonators or networks using surface acoustic waves
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02535—Details of surface acoustic wave devices
    • H03H9/02818—Means for compensation or elimination of undesirable effects
    • H03H9/02897—Means for compensation or elimination of undesirable effects of strain or mechanical damage, e.g. strain due to bending influence
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/125—Driving means, e.g. electrodes, coils
    • H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves
    • H03H9/14538—Formation
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/25—Constructional features of resonators using surface acoustic waves
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/07—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base
    • H10N30/072—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by laminating or bonding of piezoelectric or electrostrictive bodies
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/704—Piezoelectric or electrostrictive devices based on piezoelectric or electrostrictive films or coatings
    • H10N30/706—Piezoelectric or electrostrictive devices based on piezoelectric or electrostrictive films or coatings characterised by the underlying bases, e.g. substrates
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/88—Mounts; Supports; Enclosures; Casings

Definitions

  • the present invention relates to a bonded body of a specific piezoelectric material layer and a supporting substrate of mullite.
  • acoustic wave devices functioning as filter devices or oscillators used in mobile phones or the like, and acoustic wave devices such as lamb wave devices or film bulk acoustic resonators (FBAR) using a piezoelectric thin film are known.
  • acoustic wave device a device produced by adhering a supporting substrate and a piezoelectric substrate propagating a surface acoustic wave, and by providing interdigitated electrodes capable of oscillating the surface acoustic wave on a surface of the piezoelectric substrate, is known.
  • the change of size of the piezoelectric substrate responsive to temperature change is reduced so that the change of the frequency characteristics as the surface acoustic wave device are reduced.
  • a surface acoustic wave device having a structure produced by adhering a piezoelectric substrate and silicon substrate with an adhesive layer composed of an epoxy adhering agent is disclosed.
  • a silicon oxide film is formed on a surface of the piezoelectric substrate and that a silicon substrate and the piezoelectric substrate are bonded through the silicon oxide film (patent document 2).
  • a plasma beam is irradiated onto the surfaces of the silicon oxide film and the silicon substrate to activate the surfaces, followed by the direct boding (Plasma activation method).
  • a filler layer may be provided on the roughened surface to provide a flattened surface, and a filler layer is adhered onto a silicon substrate through an adhering layer (patent document 3).
  • an epoxy-based or acryl-based resin is used for the filler layer and adhering layer, and the bonding surface of the piezoelectric substrate is the roughened surface to reduce the reflection of bulk wave and to reduce spurious wave.
  • a direct bonding method of a so-called FAB (Fast Atom Beam) system (patent document 4) is known. According to this method, a neutralized atomic beam is irradiated onto the respective bonding surfaces at ambient temperature to activate them, followed by direct bonding.
  • FAB Fast Atom Beam
  • Patent document 1 Japanese patent publication No. 2010-187373A
  • Patent document 2 U.S. Pat. No. 7,213,314 B2
  • Patent document 3 Japanese Patent No. 5,814,727 B
  • Patent document 4 Japanese Patent Publication No. 2014-086400A
  • the inventors have researched bonding a supporting substrate, particularly composed of mullite, onto a piezoelectric material layer composed of lithium niobate or lithium tantalate strongly and stably.
  • the reason is that it is preferred to make the piezoelectric material layer thin by polishing after the supporting substrate is bonded to the piezoelectric material layer in light of the performance and that fine separation occurs during the polishing if the bonding strength is low.
  • An object of the present invention is to provide microstructure capable of bonding the piezoelectric material layer composed of lithium niobate or lithium tantalate onto the supporting substrate composed of mullite strongly and stably.
  • the present invention provides a bonded body comprising a supporting substrate and a piezoelectric material layer, said supporting substrate comprising mullite, and said piezoelectric material layer comprising a material comprising LiAO 3
  • A represents one or more element selected from the group consisting of niobium and tantalum
  • said bonded body comprises an interface layer present along an interface between said supporting substrate and said piezoelectric material layer, and a supporting substrate-side intermediate layer present between said interface layer and said supporting substrate; and wherein each of said interface layer and said supporting substrate-side intermediate layer comprises oxygen, aluminum, silicon and one or more element selected from the group consisting of niobium and tantalum, as main components.
  • FIG. 1 ( a ) is a diagram schematically showing a bonded body 1 according to an embodiment of the present invention
  • FIG. 1 ( b ) is an enlarged view of a part of the bonded body 1 .
  • FIG. 2 is a photograph showing a part of a bonded body according to an embodiment of the present invention.
  • FIG. 3 is a diagram illustrating the photograph of FIG. 2 .
  • FIG. 4 ( a ) shows a state that a surface 2 c of a piezoelectric material layer 2 is activated by a neutralized beam A
  • FIG. 4 ( b ) shows a state that a surface 3 c of a supporting substrate 3 is activated by neutralized beam A.
  • FIG. 5 ( a ) shows a state that the piezoelectric material layer 2 and supporting substrate 3 are bonded with each other
  • FIG. 5 ( b ) shows a state that a piezoelectric material layer 2 A is thinned by processing
  • FIG. 5 ( c ) shows a state that an electrode 9 is provided on the piezoelectric material layer 2 A.
  • the bonded body of the present invention includes a supporting substrate and a piezoelectric material layer, the supporting substrate being composed of mullite, and the piezoelectric material substrate made of a material of LiAO 3 (A represents one or more element selected from the group consisting of niobium and tantalum).
  • A represents one or more element selected from the group consisting of niobium and tantalum.
  • an activated surface 3 a of a supporting substrate 3 is bonded to an activated surface 2 a of a piezoelectric material layer 2 by direct bonding.
  • 2 b represents a main surface of the piezoelectric material layer 2
  • 3 b represents a main surface of the supporting substrate 3 .
  • a bonding interface of the bonded body of FIG. 1 ( a ) is enlarged and shown as a schematic diagram in FIG. 1 ( b ) .
  • An interface layer 4 is provided along an interface between the supporting substrate 3 and piezoelectric material layer 2 , and a supporting substrate-side intermediate layer 5 is present between the interface layer 4 and supporting substrate 3 .
  • Each of the interface layer 4 and supporting substrate-side intermediate layer 5 is composed of a material containing one or more element selected from the group consisting of niobium or tantalum, and oxygen, aluminum and silicon as main components.
  • the material of the piezoelectric material layer is LiAO 3 .
  • A represent one or more element selected from the group consisting of niobium and tantalum.
  • LiAO 3 may be lithium niobate, lithium tantalate or lithium niobate-lithium tantalate solid solution.
  • the supporting substrate is composed of mullite.
  • Mullite is a ceramic composed of mullite crystals each having a composition of 3Al 2 O 3 .2SiO 2 (Al 6 O 13 Si 2 ).
  • Mullite may preferably be of a sintered body, and its production method is not particularly limited.
  • the relative density of mullite used in the present invention may preferably be 99.5 percent or higher and may be 100 percent, depending on bonding strength.
  • the relative density is to be measured by the Archimedes method.
  • the purity of mullite may preferably be 98 percent or higher and more preferably be 99 percent or higher, depending on bonding strength.
  • compositions of the respective layers shown in FIGS. 1 ( b ) and 2 are as follows.
  • composition of supporting substrate Al 6 O 13 Si 2
  • each of the interface layer and supporting substrate-side intermediate layer contains one or more element (A) selected from the group consisting of niobium and tantalum, plus oxygen (O), aluminum (Al) and silicon (Si) as main components.
  • element (A) selected from the group consisting of niobium and tantalum diffuses from the piezoelectric material layer 2 to the side of the supporting substrate 3 .
  • element (Al) and silicon (Si) diffuse from the supporting substrate 3 (Al 6 O 13 Si 2 ) to the piezoelectric material layer (LiAO 3 ).
  • the piezoelectric material layer composed of lithium niobate or lithium tantalate can be bonded onto the supporting substrate composed of mullite strongly and stably, by applying such a microstructure.
  • the material contains one or more element (A) selected from the group consisting of niobium and tantalum, plus oxygen (O), aluminum (Al) and silicon (Si)” as “main components” means that a total of these elements is 95 atomic percent or higher and may preferably be 97 atomic percent or higher, provided that 100 is assigned to a total of all the elements.
  • A element selected from the group consisting of niobium and tantalum, plus oxygen (O), aluminum (Al) and silicon (Si)
  • main components means that a total of these elements is 95 atomic percent or higher and may preferably be 97 atomic percent or higher, provided that 100 is assigned to a total of all the elements.
  • the silicon ratio of the supporting substrate-side intermediate layer 5 should be higher than the silicon ratio of the interface layer 4 .
  • the supporting substrate-side intermediate layer and interface layer are very thin, so that the diffusion of silicon is facilitated depending on the activation state of each bonding surface. It is thus considered that the diffusion of silicon is concentrated in the interface layer 4 slightly distant from the supporting substrate 3 . Then, it is found that the bonding strength is considerably improved when such diffusion takes place.
  • the interface layer 4 is bright and the supporting substrate-side intermediate layer 5 is dark.
  • this photograph is a bright-field image taken by a transmission type electron microscope under the following conditions.
  • the microstructure is observed using a transmission type electron microscope (supplied by JEOL Ltd., “JEM-ARM200F”).
  • a sample is thinned by FIB (Focused Ion Beam) method and observed at an acceleration voltage of 200 kV.
  • each of the atomic ratios of the supporting substrate, supporting substrate-side intermediate layer, interface layer and piezoelectric material layer is determined as follows.
  • a sample is thinned by FIB (Focused Ion Beam) method and observed at an acceleration voltage of 200 kV, an X-ray take-off angle of 21.9°, a solid angle of 0.98sr and a capture time of 30 seconds.
  • FIB Fluorine-Beam
  • Atomic ratios of one or more of element (A) selected from the group consisting of niobium and tantalum, oxygen (O), aluminum (Al), silicon (Si) and argon (Ar) are measured at the respective parts of the piezoelectric material layer, interface layer, supporting substrate-side intermediate layer and supporting substrate.
  • the atomic ratio of the element (A) is a total of the ratios of Ta and Nb.
  • the respective atomic ratios (atom %) of the respective atoms are calculated so that 100% is assigned to a total of the atomic ratios of the respective elements.
  • the atomic ratios of aluminum (Al) and silicon (Si) of the supporting substrate are converted to 100, and, responsive to this, the atomic ratios of aluminum (Al) and silicon (Si) of the other layers are calculated. These are indications of the diffusion of aluminum and silicon from the supporting substrate to the other respective layers.
  • the atomic ratios of aluminum (Al) and silicon (Si) are 0.
  • the atomic ratio of one or more element (A) selected from the group of niobium and tantalum of the piezoelectric material layer is converted to 100, and, responsive to this, the atomic ratios of the element (A) of the respective layers are calculated. These are indications of the diffusion of the element (A) from the piezoelectric material layer to the other respective layers.
  • the atomic ratio of the element (A) of the supporting substrate is 0.
  • the silicon ratio of the interface layer is 41 or higher, provided that 100 is assigned to the silicon ratio of the supporting substrate. By elevating the ratio to 41 or higher, the bonding strength is further improved.
  • the silicon ratio of the interface layer may preferably be 51 or higher and more preferably be 61 or higher.
  • the silicon ratio of the interface layer is 98 or lower, provided that 100 is assigned to the silicon ratio of the supporting substrate.
  • the silicon ratio of the interface layer may preferably be 89 or lower and more preferably be 79 or lower.
  • the silicon ratio of the interface layer may be lower than the silicon ratio of the supporting substrate-side intermediate layer.
  • a difference between the silicon ratios of the interface layer and the supporting substrate-side intermediate layer may preferably be 21 or smaller and more preferably be 12 or smaller, provided that 100 is assigned to the silicon ratio of the supporting substrate.
  • the silicon ratio of the interface layer is higher than the silicon ratio of the supporting substrate-side intermediate layer.
  • a difference between the silicon ratios of the interface layer and supporting substrate-side intermediate layer may preferably be 19 or larger and more preferably be 38 or larger.
  • the aluminum ratio of the supporting substrate-side intermediate layer is higher than the aluminum ratio of the supporting substrate. This means that, in the supporting substrate-side intermediate layer, aluminum (Al) diffused from the supporting substrate is concentrated locally. The bonding strength tends to be particularly high in this case.
  • the aluminum ratio of the supporting substrate-side intermediate layer may preferably be 105 or higher and more preferably be 112 or higher, provided that 100 is assigned to the aluminum ratio of the supporting substrate. Further, in actuality, the aluminum ratio of the supporting substrate-side intermediate layer is 116 or lower in many cases.
  • the aluminum ratio of the interface layer may preferably be 31 or higher depending on bonding strength and usually 45 or lower, provided that 100 is assigned to the aluminum ratio of the supporting substrate. Further, the aluminum ratio of the interface layer may preferably be lower than the aluminum ratio of the supporting substrate-side intermediate layer.
  • One or more element (A) selected from the group consisting of niobium and tantalum diffuses from the piezoelectric material layer to the supporting substrate.
  • the atomic ratio of the element (A) of the interface layer may preferably be 50 to 90 and more preferably be 60 to 88, provided that 100 is assigned to the atomic ratio of the element (A) of the piezoelectric material layer.
  • the atomic ratio of the element (A) of the supporting substrate-side intermediate layer may preferably be 6 to 30 and more preferably be 16 to 23.
  • the atomic ratio of the element (A) of the supporting substrate-side intermediate layer is usually lower than the atomic ratio of the element (A) of the interface layer.
  • the atomic ratio of a carrier gas such as argon (Ar) of the interface layer may preferably be 1.8 to 2.5 atom %. Further, the atomic ratio of a carrier gas such as argon (Ar) of the supporting substrate-side intermediate layer may preferably be 0.1 to 0.5 atom %.
  • FIGS. 4 and 5 are diagrams for illustrating a production example of directly bonding a supporting substrate onto a surface of the piezoelectric material layer.
  • a neutralized beam is irradiated onto a surface 2 c of a piezoelectric material layer 2 as arrows A to activate the surface of the piezoelectric material layer 2 to provide an activated surface.
  • a neutralized beam A is irradiated onto the surface 3 c of the supporting substrate 3 to activate it to provide the supporting substrate having an activated surface formed thereon.
  • the activated surface 2 a of the piezoelectric material layer 2 and the activated surface 3 a of the supporting body 3 are bonded by direct bonding, to obtain a bonded body 1 .
  • the surface 2 b of the piezoelectric material layer 2 of the bonded body 1 is further subjected to a polishing process to make the thickness of the piezoelectric material layer 2 A smaller as shown in FIG. 5 ( b ) to obtain a bonded body 7 .
  • 2 d represents a polished surface.
  • electrodes 9 are formed on the polished surface 2 d of the piezoelectric material layer 2 A to produce a surface acoustic wave device 8 .
  • bonded body of the present invention are not particularly limited, and the bonded body may be appropriately applied to an acoustic wave device and optical device, for example.
  • the acoustic wave device As the acoustic wave device, a surface acoustic wave device, Lamb wave-type device, thin film resonator (FBAR) or the like may be produced.
  • the surface acoustic wave device is produced by providing input side IDT (Interdigital transducer) electrodes (also referred to as comb electrodes or interdigitated electrodes) for oscillating surface acoustic wave and IDT electrodes on the output side for receiving the surface acoustic wave, on the surface of the piezoelectric material layer.
  • IDT Interdigital transducer
  • IDT electrodes also referred to as comb electrodes or interdigitated electrodes
  • an electric field is generated between the electrodes, so that the surface acoustic wave is oscillated and propagated on the piezoelectric material layer.
  • the propagated surface acoustic wave can be drawn as an electrical signal from the IDT electrodes on the output side provided in the direction of the propagation.
  • a metal film may be provided on a bottom surface of the piezoelectric material layer.
  • the metal film plays a role of improving the electro-mechanical coupling factor near the bottom surface of the piezoelectric material layer.
  • the Lamb type device has a structure such that interdigitated electrodes are formed on the surfaces of the piezoelectric material layer and the metal film on the piezoelectric material layer is exposed through a cavity provided in the supporting substrate.
  • the material of such a metal film includes aluminum, an aluminum alloy, copper, gold or the like, for example.
  • a composite substrate having the piezoelectric material layer without the metal film on the bottom surface may be used.
  • a metal film and an insulating film may be provided on the bottom surface of the piezoelectric material layer.
  • the metal film plays the role of electrodes in the case that a thin film resonator is produced as the acoustic wave device.
  • the thin film resonator has a structure such that electrodes are formed on the upper and bottom surfaces of the piezoelectric material layer, and the insulating film has a cavity to expose the metal film on the piezoelectric material layer.
  • the material of such a metal film includes molybdenum, ruthenium, tungsten, chromium, aluminum or the like, for example.
  • the material of the insulating film includes silicon dioxide, phosphorus silicate glass, boron phosphorus silicate glass or the like.
  • the optical device it may be an optical switching device, wavelength conversion device, or optical modulating device. Further, a periodic domain inversion structure may be formed in the piezoelectric material layer.
  • the layer in which it is rotated is preferably at an angle of 36 to 47° (for example 42°) from Y-axis toward Z-axis around X-axis, the direction of propagation of surface acoustic wave, thanks to the low propagation loss.
  • the layer in which it is rotated is preferably at an angle of 60 to 68° (for example 64°) from Y-axis toward Z-axis around X-axis, the direction of propagation of surface acoustic wave, thanks to the low propagation loss.
  • the size of the piezoelectric material layer is not particularly limited, the diameter is preferably 50 to 150 mm and the thickness 0.2 to 60 ⁇ m, for example.
  • the following method is preferred for obtaining the bonded body of the present invention.
  • the surfaces (bonding surfaces) of the piezoelectric material layer and supporting substrate are flattened to obtain flat surfaces.
  • the method of flattening each of the surfaces includes lapping, chemical mechanical polishing or the like.
  • the flat surface may preferably have Ra of 1 nm or less and more preferably have Ra of 0.3 nm or less.
  • the surfaces of the piezoelectric material layer and supporting substrate are cleaned.
  • the method of cleaning the surfaces includes wet cleaning, dry cleaning, scrub cleaning or the like, and scrub cleaning is preferred for obtaining cleaned surfaces easily and efficiently.
  • a neutralized beam is then irradiated onto the surfaces of the piezoelectric material layer and supporting substrate to activate the respective flat surfaces.
  • a neutralized beam is used to perform the surface activation
  • a system such as that described in patent document 4 to generate the neutralized beam, which is then irradiated. That is, a source of high-speed atomic beam of saddle field type as a beam source may be used. Inert gas is then introduced into a chamber and a high voltage is applied onto the electrodes from a direct current electric source. An electric field of saddle-field type is generated between the electrode (positive electrode) and a housing (negative electrode), so that electrons e are moved to generate beams of atoms and ions from the inert gas.
  • the beam of the ions is neutralized at the grid so that the beam of the neutral atoms is emitted from the high-speed atomic beam source.
  • Atomic particles forming the beam may preferably be that from an inert gas (argon, nitrogen or the like).
  • a voltage and current at the time of activation by irradiation of the beam may preferably be 0.5 to 2.0 kV and 50 to 200 mA, respectively.
  • the activated surfaces are contacted and bonded with each other under vacuum atmosphere.
  • This process is performed under ambient temperature, which is preferably 40° C. or lower and more preferably 30° C. or lower.
  • the temperature during the bonding step may preferably be 20° C. or higher and more preferably be 25° C. or lower.
  • the pressure during the bonding step may preferably be 100 to 20000N.
  • a bonded body was obtained, according to the method described referring to FIGS. 4 and 5 .
  • a piezoelectric material layer 2 of lithium tantalate (LT) having an orientation flat (OF) part, a diameter of 4 inches, and thickness of 250 ⁇ m was prepared.
  • the piezoelectric material layer 2 was used as a 46° Y-cut X-propagation LT substrate, in which the direction of propagation of the surface acoustic wave (SAW) is X and the Y-cut plate is rotated in a cutting angle.
  • the surface 2 c of the piezoelectric material layer 2 was mirror-polished to an arithmetic average roughness Ra of 1 nm.
  • a mullite substrate having an OF part, a diameter of 4 inches, and a thickness of 230 ⁇ m was prepared as the supporting substrate 3 .
  • the surfaces 3 c of the supporting substrate 3 of mullite had an arithmetic average roughness Ra of 0.3 nm.
  • the arithmetic average roughness was evaluated by means of an atomic force microscope (AFM) in a square visual field of a length of 10 ⁇ m and a width of 10 ⁇ m.
  • AFM atomic force microscope
  • the supporting substrate 3 was then cleaned by a scrub cleaner. “Semi-clean M-LO” was used as the cleaning liquid and a mixed solution of acetone and IPA was then used as cleaning liquid.
  • the supporting substrate 3 and piezoelectric material layer 2 were cleaned by means of a scrub cleaning machine and then introduced into a vacuum chamber. The inside was drawn to a vacuum of 10 ⁇ 6 Pa, and a high-speed atomic beam (at an acceleration voltage of 0.5 kV and a flow rate of Ar of 27 sccm) was irradiated onto each of the bonding surfaces of the substrates over 120 sec.
  • the surface 2 a with the beam irradiated surface (activated surface) of the piezoelectric material layer 2 and the activated surface 3 a of the supporting substrate 3 were then contacted with each other, followed by pressurizing at 10000N over 2 minutes to bond the substrates ( FIG. 5 ( a ) ).
  • the obtained bonded body was then subjected to the measurement of the respective atomic ratios of oxygen (O), aluminum (Al), silicon (Si), tantalum (Ta) and argon (Ar) of the piezoelectric material layer, interface layer, supporting substrate-side intermediate layer and supporting substrate, respectively.
  • O oxygen
  • Al aluminum
  • Si silicon
  • Ta tantalum
  • Ar argon
  • Comparative Example 1 is out of the scope of the present invention, as silicon is not contained in the interface layer.
  • the obtained bonded body was subjected to evaluation of bonding strength by a crack-opening method and obtained a value of 0.5 J/m 2 . Further, the surface 2 b of the piezoelectric material layer 2 was ground and polished so that the thickness was changed from the initial 250 ⁇ m to 30 ⁇ m. Peeling of the bonded part occurred during the grinding and polishing steps.
  • a bonded body was produced according the same procedure as Comparative Example 1. However, the acceleration voltage irradiated onto the bonding surfaces of the substrates during the bonding was changed to 0.6 kV.
  • the obtained bonded body was then subjected to the measurement of the respective atomic ratios of oxygen (O), aluminum (Al), silicon (Si), tantalum (Ta) and argon (Ar) of the piezoelectric material layer, interface layer, supporting substrate-side intermediate layer and supporting substrate, respectively.
  • O oxygen
  • Al aluminum
  • Si silicon
  • Ta tantalum
  • Ar argon
  • the obtained bonded body was subjected to evaluation of bonding strength by the crack-opening method and obtained a value of 0.75 J J/m 2 .
  • the surface 2 b of the piezoelectric material layer 2 was ground and polished so that the thickness was changed from the initial 250 ⁇ m to 30 ⁇ m. Peeling of the bonded part did not occur during the grinding and polishing steps. As it was further ground and polished to a thickness of 20 ⁇ m, peeling of the bonded part occurred during the grinding and polishing steps.
  • Bonded bodies were produced according the same procedure as the Comparative Example 1. However, the acceleration voltages irradiated onto the bonding surfaces of the substrates during the bonding were changed to 1.0 kV, 1.2 kV and 1.5 kV in the Inventive Examples 2, 3 and 4, respectively.
  • the obtained bonded bodies were then subjected to the measurement of the respective atomic ratios of oxygen (O), aluminum (Al), silicon (Si), tantalum (Ta) and argon (Ar) of the piezoelectric material layer, interface layer, supporting substrate-side intermediate layer and supporting substrate, respectively.
  • O oxygen
  • Al aluminum
  • Si silicon
  • Ta tantalum
  • Ar argon
  • the obtained bonded bodies were subjected to evaluation of bonding strength by the crack-opening method, and bulk fracture occurred in all of the bonded bodies. Further, the surfaces 2 b of the piezoelectric material layers 2 were ground and polished so that the thickness were changed from the initial 250 ⁇ m to 20 ⁇ m. Peeling of the bonded part did not occur during the grinding and polishing steps.

Landscapes

  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
US16/796,036 2017-08-25 2020-02-20 Joined body and elastic wave element Active 2039-12-26 US11637541B2 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2017162223 2017-08-25
JP2017-162223 2017-08-25
JPJP2017-162223 2017-08-25
PCT/JP2018/030853 WO2019039474A1 (ja) 2017-08-25 2018-08-21 接合体および弾性波素子

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2018/030853 Continuation WO2019039474A1 (ja) 2017-08-25 2018-08-21 接合体および弾性波素子

Publications (2)

Publication Number Publication Date
US20200195217A1 US20200195217A1 (en) 2020-06-18
US11637541B2 true US11637541B2 (en) 2023-04-25

Family

ID=65438891

Family Applications (1)

Application Number Title Priority Date Filing Date
US16/796,036 Active 2039-12-26 US11637541B2 (en) 2017-08-25 2020-02-20 Joined body and elastic wave element

Country Status (7)

Country Link
US (1) US11637541B2 (de)
JP (2) JP6563616B2 (de)
KR (1) KR102413290B1 (de)
CN (1) CN110945787B (de)
DE (1) DE112018003634B4 (de)
TW (1) TWI692463B (de)
WO (1) WO2019039474A1 (de)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE112018003634B4 (de) 2017-08-25 2024-05-02 Ngk Insulators, Ltd. Verbundener Körper und elastische Welle-Element
WO2019039475A1 (ja) 2017-08-25 2019-02-28 日本碍子株式会社 接合体および弾性波素子
JP6761919B1 (ja) * 2019-06-11 2020-09-30 日本碍子株式会社 複合基板および弾性波素子
WO2021106572A1 (ja) * 2019-11-29 2021-06-03 日本碍子株式会社 圧電性材料基板と支持基板との接合体
KR20220007691A (ko) * 2020-04-21 2022-01-18 지난 징젱 일렉트로닉스 씨오., 엘티디. 복합 기판 및 이의 제조방법
US20230291384A1 (en) * 2020-07-30 2023-09-14 Kyocera Corporation Elastic wave element, ladder filter, demultiplexer, and communication apparatus

Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000312130A (ja) 1999-04-28 2000-11-07 Matsushita Electric Ind Co Ltd 圧電デバイス及びその製造方法とこれらを用いた移動体通信装置
US20040226162A1 (en) 2003-05-14 2004-11-18 Fujitsu Media Devices Limited Method and manufacturing surface acoustic wave device
US7213314B2 (en) 2002-07-03 2007-05-08 Triquint, Inc. Method of forming a surface acoustic wave (SAW) filter device
US20100182101A1 (en) 2009-01-19 2010-07-22 Ngk Insulators, Ltd. Composite substrate and elastic wave device using the same
US20120086312A1 (en) 2010-10-06 2012-04-12 Hiroki Kobayashi Composite substrate manufacturing method and composite substrate
JP2012213244A (ja) 2007-12-25 2012-11-01 Murata Mfg Co Ltd 複合圧電基板の製造方法
JP2014086400A (ja) 2012-10-26 2014-05-12 Mitsubishi Heavy Ind Ltd 高速原子ビーム源およびそれを用いた常温接合装置
JP2014147054A (ja) 2013-01-30 2014-08-14 Sumitomo Electric Ind Ltd 圧電基板及び弾性表面波素子
WO2014192597A1 (ja) 2013-05-31 2014-12-04 日本碍子株式会社 複合基板用支持基板および複合基板
WO2015186560A1 (ja) 2014-06-06 2015-12-10 日本碍子株式会社 ムライト焼結体、その製法及び複合基板
WO2017047604A1 (ja) 2015-09-15 2017-03-23 日本碍子株式会社 複合基板の製造方法
US20170093371A1 (en) * 2014-06-26 2017-03-30 Murata Manufacturing Co., Ltd. Longitudinally coupled resonator-type surface acoustic wave filter
WO2017134980A1 (ja) 2016-02-02 2017-08-10 信越化学工業株式会社 複合基板および複合基板の製造方法
WO2019039474A1 (ja) 2017-08-25 2019-02-28 日本碍子株式会社 接合体および弾性波素子

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5814727B2 (ja) 1974-09-25 1983-03-22 富士写真フイルム株式会社 キヨウジセイサンカテツノ セイホウ
JP2011087079A (ja) * 2009-10-14 2011-04-28 Ngk Insulators Ltd 弾性表面波素子
KR101511001B1 (ko) 2012-11-14 2015-04-10 엔지케이 인슐레이터 엘티디 복합 기판

Patent Citations (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000312130A (ja) 1999-04-28 2000-11-07 Matsushita Electric Ind Co Ltd 圧電デバイス及びその製造方法とこれらを用いた移動体通信装置
US7213314B2 (en) 2002-07-03 2007-05-08 Triquint, Inc. Method of forming a surface acoustic wave (SAW) filter device
US20040226162A1 (en) 2003-05-14 2004-11-18 Fujitsu Media Devices Limited Method and manufacturing surface acoustic wave device
JP3774782B2 (ja) 2003-05-14 2006-05-17 富士通メディアデバイス株式会社 弾性表面波素子の製造方法
US8973229B2 (en) 2007-12-25 2015-03-10 Murata Manufacturing Co., Ltd. Method for manufacturing composite piezoelectric substrate
JP2012213244A (ja) 2007-12-25 2012-11-01 Murata Mfg Co Ltd 複合圧電基板の製造方法
US20100182101A1 (en) 2009-01-19 2010-07-22 Ngk Insulators, Ltd. Composite substrate and elastic wave device using the same
JP2010187373A (ja) 2009-01-19 2010-08-26 Ngk Insulators Ltd 複合基板及びそれを用いた弾性波デバイス
JP5814727B2 (ja) 2010-10-06 2015-11-17 日本碍子株式会社 複合基板の製造方法及び複合基板
US20120086312A1 (en) 2010-10-06 2012-04-12 Hiroki Kobayashi Composite substrate manufacturing method and composite substrate
JP2014086400A (ja) 2012-10-26 2014-05-12 Mitsubishi Heavy Ind Ltd 高速原子ビーム源およびそれを用いた常温接合装置
JP2014147054A (ja) 2013-01-30 2014-08-14 Sumitomo Electric Ind Ltd 圧電基板及び弾性表面波素子
WO2014192597A1 (ja) 2013-05-31 2014-12-04 日本碍子株式会社 複合基板用支持基板および複合基板
US20160049469A1 (en) 2013-05-31 2016-02-18 Ngk Insulators, Ltd. Supporting substrate for composite substrate and composite substrate
US9776924B2 (en) 2014-06-06 2017-10-03 Ngk Insulators, Ltd. Mullite sintered body, method for producing the same, and composite substrate
WO2015186560A1 (ja) 2014-06-06 2015-12-10 日本碍子株式会社 ムライト焼結体、その製法及び複合基板
US20170093371A1 (en) * 2014-06-26 2017-03-30 Murata Manufacturing Co., Ltd. Longitudinally coupled resonator-type surface acoustic wave filter
WO2017047604A1 (ja) 2015-09-15 2017-03-23 日本碍子株式会社 複合基板の製造方法
US20170179371A1 (en) 2015-09-15 2017-06-22 Ngk Insulators, Ltd. Production method for composite substrate
US9935257B2 (en) * 2015-09-15 2018-04-03 Ngk Insulators, Ltd. Production method for composite substrate
WO2017134980A1 (ja) 2016-02-02 2017-08-10 信越化学工業株式会社 複合基板および複合基板の製造方法
JP2017139720A (ja) 2016-02-02 2017-08-10 信越化学工業株式会社 複合基板および複合基板の製造方法
US20190036505A1 (en) 2016-02-02 2019-01-31 Shin-Etsu Chemical Co., Ltd. Composite substrate and method of manufacturing composite substrate
WO2019039474A1 (ja) 2017-08-25 2019-02-28 日本碍子株式会社 接合体および弾性波素子

Non-Patent Citations (7)

* Cited by examiner, † Cited by third party
Title
English Decision to Grant a Patent for JP 6563616B (Application No. 2018-566327) (2 pages).
English Notice of Reasons for Refusal for JP 6563616B (Application No. 2018-566327) (3 pages).
Japanese International Search Opinion with English Translation for corresponding PCT/JP2018/030853, dated Mar. 5, 2020 (14 pages).
Japanese International Search Report for corresponding PCT/JP2018/030853, dated Oct. 30, 2018 (3 pages).
Japanese Written Opinion for corresponding PCT/JP2018/030853, dated Oct. 30, 2018 (4 pages).
Korean Office Action with English translation issued in corresponding Korean Application No. 10-2020-7005129 dated May 25, 2021 (8 pages).
Notice of Reasons for Refusal with English Translation for corresponding JP Application No. 2019-093433, dated Jan. 23, 2020 (12 pages).

Also Published As

Publication number Publication date
JP6563616B2 (ja) 2019-08-21
KR102413290B1 (ko) 2022-06-27
JPWO2019039474A1 (ja) 2019-11-07
KR20200028478A (ko) 2020-03-16
WO2019039474A1 (ja) 2019-02-28
DE112018003634T5 (de) 2020-04-23
JP2019140697A (ja) 2019-08-22
DE112018003634B4 (de) 2024-05-02
US20200195217A1 (en) 2020-06-18
CN110945787B (zh) 2023-06-02
TW201920049A (zh) 2019-06-01
JP6708773B2 (ja) 2020-06-10
TWI692463B (zh) 2020-05-01
CN110945787A (zh) 2020-03-31

Similar Documents

Publication Publication Date Title
US11637541B2 (en) Joined body and elastic wave element
US10720566B2 (en) Bonding method
US10964882B2 (en) Bonding method
US10284169B2 (en) Bonded bodies and acoustic wave devices
US11456720B2 (en) Bonded body with piezoelectric monocrystalline substrate and supporting substrate
US11632093B2 (en) Acoustic wave devices and a method of producing the same
US11984870B2 (en) Bonded body and acoustic wave element
US11888462B2 (en) Bonded body and acoustic wave element
US11133788B2 (en) Bonded body and elastic wave element
US10931256B2 (en) Joined body and elastic wave element

Legal Events

Date Code Title Description
FEPP Fee payment procedure

Free format text: ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: BIG.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

AS Assignment

Owner name: NGK INSULATORS, LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GOTO, MASASHI;TAI, TOMOYOSHI;MINOURA, MAI;REEL/FRAME:051898/0300

Effective date: 20200130

STPP Information on status: patent application and granting procedure in general

Free format text: APPLICATION DISPATCHED FROM PREEXAM, NOT YET DOCKETED

STPP Information on status: patent application and granting procedure in general

Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION

STPP Information on status: patent application and granting procedure in general

Free format text: NON FINAL ACTION MAILED

STPP Information on status: patent application and granting procedure in general

Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER

STPP Information on status: patent application and granting procedure in general

Free format text: NOTICE OF ALLOWANCE MAILED -- APPLICATION RECEIVED IN OFFICE OF PUBLICATIONS

STCF Information on status: patent grant

Free format text: PATENTED CASE